This exploratory pilot project is being submitted in response to RFA-DA-04-015, "HIV/AIDS and Other Infections among Drug Users in the Criminal Justice System" for support under the R21 mechanism. It will examine how involvement in the criminal justice (CJ) system subsequently shapes the HIV related risks and behaviors of individuals with a history of drug use, and how this varies by race and gender. It will focus in particular on understanding how the criminal justice system operates as a structural determinant of both drug- and sexual-related HIV risk in drug users (DUs), and with this understanding, on identifying potential structural interventions-modifications in the CJ system-for promoting HIV prevention among DUs. The project will examine these issues from the perspective of the individual, in order to better understand the HIV prevention needs of DUs involved with the CJ system, and from the perspective of the CJ system, in order to understand where there may be opportunities for reforms or for utilizing CJ personnel to promote HIV prevention (potential structural interventions). With regard to the individual, it will examine three specific mechanisms through which the CJ system is hypothesized to impact on risk among DUs, including, through its effects on: social support networks and family relationships, socio-economic vulnerability, and access to risk reduction programs. With regard to the CJ system, it will focus on the systems of probation and parole (PIP), including laws and regulations relating to P/P, as well as the responsibilities and authority invested in key actors in these systems (e.g. probation and parole officers, attorneys, and judges) and how they exercise this authority.